senile

The word 'senile' has a direct lineage from the Latin senilis, an adjective meaning 'of an old man, aged', which itself derives from senex (old man, aged). This Latin root is traceable to the Proto-Indo-European root sen- (old), a concept also preserved in other languages, such as Greek henos (old) and Sanskrit sána- (old). The literal meaning, 'pertaining to an old man', evolved in medical and general English to specifically denote the physical and, most notably, the mental infirmities associated with advanced age. Thus, the modern abstract meaning shifted from a neutral descriptor of age to one emphasizing its characteristic decline.

Structure: sen (old) + ile (adjective suffix) The morpheme 'sen' originates from Latin senex meaning 'old man, aged'. The morpheme '-ile' is a Latin-derived adjectival suffix (-ilis) meaning 'pertaining to, capable of, or having the nature of'.